Effect of dental bleaching on pulp oxygen saturation in maxillary central incisors - a randomized clinical trial

Pulse oximetry as a dental pulp test: A scoping review to identify barriers hindering the use of oximeters in clinical practice

Background and Objective

Although medical pulse oximeters are considered effective for endodontic diagnoses, the method remains uncommon in current dental practice. The aim of the present scoping review was to investigate clinical factors that exert a negative impact on the use of pulse oximeters in dental practice.

Methods

This study followed the PRISMA-ScR guidelines and the protocol was prospectively registered in the Open Science Framework (https://doi.org/10.17605/OSF.IO/3GQCE). A comprehensive search of the MEDLINE (via PubMed), Cochrane Library, and Web of Science databases was performed in December 2022 for articles published in English or Spanish. All types of clinical studies were included, except comments, letters to the editor, and abstracts. Two independent investigators analyzed 45 full-text articles. Data extraction included general characteristics, oxygen saturation levels, and limiting factors/barriers to the use of oximeters as pulp testers.

Results

The search of the databases yielded 1,300 records and 38 were included (quantitative data extraction was performed for 35 and three articles were systematic reviews). Publications were highest in number between 2016 and 2017, with an evident reduction occurring after 2021. The oxygen saturation level for sound/vital maxillary anterior teeth was 84.99% (overall mean). The main limiting factors/barriers were i) the difficulty in maintaining the two light-emitting diodes parallel during pulp tests, ii) infrared light diffraction by enamel/dentin/gingiva, and iii) the diversity of patient ages in studies.

Conclusion

This scoping review encountered noteworthy findings associated with the impracticability of using medical pulse oximeters as dental pulp testers. The recent decrease in the frequency of published studies compared to approximately seven years ago may imply a negative trend in the use of the method.

Reference values for pulp oxygen saturation as a diagnostic tool in endodontics: a systematic review and meta-analysis

Objectives

This systematic review aimed to identify mean oxygen saturation values (SpO₂) using pulse oximetry in permanent maxillary anterior teeth.

Materials and Methods

The MEDLINE, Scientific Electronic Library Online, Cochrane Central Register of Controlled Trials, EMBASE, and Literatura Latino Americana em Ciências da Saúde electronic databases were searched. Combinations and variations of “oximetry” AND “dental pulp test” were used as search terms. Studies reporting means and standard deviations of SpO₂ values were included. Two reviewers independently extracted data following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Heterogeneity was assessed using the I² statistic, and all analyses were performed using R software. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool and the Newcastle-Ottawa scale.

Results

Of the 251 studies identified, 19 met the eligibility criteria and were included (total sample, 4,541 teeth). In the meta-analysis, the mean SpO₂ values were 84.94% (95% confidence interval [CI], 84.85%–85.04%) for the central incisors, 89.29% (95% CI, 89.22%–89.35%) for the lateral incisors, and 89.20% (95% CI, 89.05%–89.34%) for the canines. The studies were predominantly low-quality due to the high risk of bias associated with the index test, unclear risk regarding patient selection, and concerns about outcome assessment.

Conclusions

Although most studies were low-quality, the oxygen saturation levels in normal pulp could be established (minimum saturation, 77.52%). Despite the risk of bias of the included studies, the reference values reported herein are clinically relevant for assessments of changes in pulp status.

Trial Registration

International Prospective Register of Systematic Reviews Identifier: CRD42018085598

Evaluation of reservoirs in bleaching trays for at-home bleaching: a split-mouth single-blind randomized controlled equivalence trial

Objectives

This randomized, split-mouth, single-blinded trial assessed whether the use of reservoirs in at-home bleaching trays is equivalent to non-reservoir trays. Our choice of an equivalence trial was based on the expectation that a non-reservoir tray is sufficient to produce a color change. Secondary outcomes such as tooth sensitivity (TS) and gingival irritation (GI) were also assessed.

Methodology

Forty-six patients were selected with canines shade A2 or darker. In half of the patient’s arch, bleaching trays were made with reservoirs and the other half, without reservoirs. At-home bleaching was performed with carbamide peroxide (CP) 10% (3 h daily; 21 days). Color change was evaluated with a digital spectrophotometer (ΔE, ΔE00, and Whiteness Index) and shade guide units (ΔSGU) at baseline, during and one-month post-bleaching. TS and GI were assessed with a numeric scale (NRS) and a visual analog scale (VAS).

Results

After one month, the equivalence of reservoir and non-reservoir groups were observed in all color instruments (p>0.05). Fifteen and sixteen patients presented pain (absolute risk: 33% and 35%, 95%, confidence interval (CI) 21-46% and 23-49%) in the reservoir and non-reservoir side, respectively. The odds ratio for pain was 0.8 (95%CI 0.2-3.0) and the p-value was non-significant (p=1.0). TS intensity was similar between both groups in any of the pain scales (p>0.05). No difference in the GI was observed (p>0.05).

Conclusions

The protocol with reservoirs is equivalent in color change to the non-reservoir, although no superiority of the latter was observed in terms of reduced TS and GI with at-home 10% carbamide peroxide bleaching.

Clinical Relevance

The presence of reservoirs in a bleaching tray did not improve color change or affect tooth sensitivity and gingival irritation.

Novel in-office peroxide-free tooth-whitening gels: bleaching effectiveness, enamel surface alterations, and cell viability

To evaluate the bleaching ability, the effect on enamel surface and cytotoxicity of novel tooth-whitening formulations containing papain, ficin, or bromelain. Forty bovine dental discs (6 cm ×4 cm) were pigmentated and randomly allocated into the following groups (n = 10): Group 1, 20 wt% carbamide peroxide (control); group 2, 1% papain-based whitening; group 3, 1% ficin-based whitening; and group 4, 1% bromelain-based whitening. The whitening gels were prepared and applied on the enamel three times per day once a week, for 4 weeks. Color measurement was obtained by CIEDE2000. Enamel Knoop microhardness and roughness were evaluated. The WST-1 assay was used to evaluate the cell viability of mouse fibroblast cells (L929). Data were statistically analyzed by one-way analysis of variance (ANOVA) and Student Newman Keuls's post hoc test at α = 0.05 significance level. Bromelain, ficin-based, and carbamide peroxide bleaching gels showed a similar color change (p < 0.001). Higher enamel hardness decrease and higher enamel roughness were caused by the carbamide peroxide (p < 0.05). The experimental whitening gels did not affect cell viability. Tooth bleaching gels containing bromelain, papain, or ficin have substantial clinical potential to be used in the development of peroxide-free tooth whitening gels.